Dizziness is a common condition affecting a large part of the population. The diagnostic and treatment for vestibular disorders requires that a patient be placed with their head in particular positions, e.g. the patient is sitting upright with the head straight and not moving. In order to perform diagnosis or treatment the patient may need to be moved to a particular position or to a predetermined set of positions in a specific order. The proper positioning of the patient's head is essential for proper diagnosis and treatment.
Since vestibular activity (i.e. a person's reaction to changes in orientation, “sense of balance”) cannot be monitored directly in a patient, a physician has to rely on secondary indications, such as the eye movement reflex, for objectively detecting activity in a person's vestibular system. When the head rotates about any axis, a person will inherently and involuntarily try to sustain distant visual images by rotating his or her eyes in the opposite direction on the respective axis. The semi-circular canals in the inner ear sense angular momentum and send signals to the nuclei for eye movement in the brain. From here, a signal is relayed to the extraocular muscles to allow his or her gaze to fixate on one object as the head moves. A particular reaction denoted nystagmus occurs when the semi-circular canals are being stimulated while the head is not in motion. The direction of eye movement is directly related to the particular semi-circular canal being stimulated.
One example of a condition which may be diagnosed and treated is Benign Paroxysmal Positional Vertigo (BPPV). BPPV is the most common cause of vertigo, accounting for nearly 40% of all vertiginous patients. The most common cause for BPPV is a displacement of the calcium-carbonated crystals (otolithic stones) present in the utricle into the semi-circular canal (canalithiasis) or onto the cupula (cupulathiasis) of the patient. Today, posterior canal BPPV (the most common) is diagnosed by performing a special sequence of particular positionings of the patient denoted a Dix-Hallpike maneuver, while the examiner simultaneously looks for nystagmus by observing the eyes when the patient is in a supine position with his or her head turned towards the affected ear. The Dix-Hallpike maneuver is the most common positioning sequence in use for diagnosing BPPV but other maneuvers such as Hallpike-Stenger, side-lying and roll are also used. The maneuver chosen is determined by physician preference, patient's neck mobility and a suspicion of whether the BPPV is present in the posterior, anterior or lateral semi-circular canal, respectively. The treatment for BPPV is through a repositioning maneuver. There are several repositioning maneuvers available to the physician for this purpose, e.g. Canalith Repositioning Treatment (denoted the Epley maneuver), Liberatory (denoted the Semant maneuver) and the so-called BBQ roll maneuver.
The maneuvers are successful in 90% of all patients treated in this manner. However, nearly 40% of the treated patients do experience reoccurrences and may need to return to the physician for additional repositioning. Why almost 40% of the treated patients do not experience immediate or lasting success from the treatment is not known. One reason could be that the repositioning maneuver may not have been properly performed by the physician. If the physician had the means to perform the repositioning maneuver at his disposal while at the same time keeping track of the patient's position and response, then the repositioning maneuver could be performed with a higher degree of confidence by the physician and a lot more patients would thus experience success from the treatment.